[Gasification] Somewhat OT, Seasons Greetings

[Tom Miles]

Greg,

Thanks for your warm greetings from the cold north. 

Fuel size is more important than most people think for both combustion and
gasification. While chunk wood gasifiers have been "demonstrated" on wood
chips in my experience with chips they produce more tars with the finer
fuels that must be cleaned downstream. Fine fuels also create important
problems in the oxidation zone of the gasifier. 

Fuel density also has an important effect on combustion, charcoal formation
and char gasification.

Identifying the appropriate size and density for a particular gasifier type
(imbert, open core, etc.) and geometry seems to be critical to making clean
gas. I have always assumed that particle size is less critical for the open
core or stratified downdraft gasifier where have you have a staged reaction
front but I now think they also have limits to fuel size and density. If you
don't get it right you have bad gas. 

Tom Miles